The invention relates to the combination of anionic grinding aids with cationic flocculating agents, an anionic flocculant containing sulphonated and/or carboxylated groups, a terpolymer and combinations thereof at the flocculating stage in mineral ore processing applications, thereby enhancing the effectiveness of mining processes particularly in the grinding and flocculating of the mineral ore slurry. The combinations of grinding aid and flocculants taught in the present application, will allow one to achieve optimum compatibility between grinding aid and flocculant(s) thereby improving the processing of mineral ores without negatively impacting at the flocculating stage. Typically the grinding aids are added to a mineral ore slurry prior to or during the process of comminuting the mineral ore in a mineral mining process. This slurry generally goes through additional process steps including wherein the mineral ore slurry is thickened by a flocculant before being further processed to obtain the desired product.
The grinding of mineral ore is a very energy intensive and inefficient stage of mineral ore processing. In an effort to make the process more efficient and cost effective, mechanical and chemical adaptations have been developed to facilitate the comminution of mineral ore. One such adaptation is the introduction of chemicals which are effective in making the grinding process more efficient. These classes of chemicals are generally anionic and can be referred to as grinding aids. Grinding aids can lower the total energy of the comminution (i.e. grinding) process while allowing for more efficient throughput of mineral ore. These chemical additives also have been shown to increase the level of fines produced during the grinding stage thus increasing grinding efficiency.
In mining applications and processes other chemicals and additives are usually added downstream from the grinding/comminuting operation to aid in processing and recovery of the desired product. In mining operations, after the grinding and comminuting of the mineral ore is accomplished, there are subsequent steps wherein the previously diluted mineral ore slurry is pumped through a conduit to a thickener tank and thickened by adding a flocculant at a flocculation stage or a similar step and further processed to obtain the desired product.
The role of the flocculant is to promote phase separation in a multi-phase system. The role of the flocculant is to enhance aggregation of the fine particles which is important in the mineral recovery strategy. However, the flocculants used in mining and mineral processing may be counteracted by the presence of grinding aids and are limited in their compatibility with grinding aids. We found a way to enhance and improve wet mineral ore grinding in mining operations through the use of a combination anionic grinding aid with flocculant. Therefore, what is needed in processing mineral ore is a combination of grinding aids and flocculants that will enhance and improve wet mineral ore grinding in mining operations.
Generally, grinding is the process in a commercial mining operation in which larger fragments of ore are broken down to particles of very fine particle sizes, i.e. the fines. The valuable minerals are extracted from the fines. The grinding process occurs in one or more means for comminuting mineral ore, such as ball mills, rod mills, autogenous mills, semi-autogenous (“SAG”) mills, pebble mills, high pressure grinding mills, burnstone mills, vertical shift impactor mills, tower mills and the like. Ball mills, SAG mills, rod mills and high pressure grinding roll mills are often used in industrial mining operations. Grinding aid compositions facilitates the comminution of the mineral ore fragments in the mineral ore slurry thus allowing grinding to the desired particle size with less total energy requirements or higher throughput. Grinding aid compositions also affects the rheology of the mineral ore slurry allowing it to flow within the mill better, with less agglomeration, allowing more efficient grinding of the mineral ore.
The mineral ore slurry comprising water and mineral ore is added to the mill either continuously, such as through a feed pipe, or manually. Typically, in mineral ore recovery processes a grinding aid composition is added to the mineral ore slurry either prior to the mineral ore slurry entering a grinding chamber(s) of the mill, such as in the feed pipe, prior to comminution or is added to the slurry when the slurry is in a grinding chamber(s) of the mill. Also, the grinding aid can be added to the mineral ore slurry both prior to the mineral ore slurry entering the mill and while the mineral ore slurry is in the grinding chamber(s) of the mill.
Once the mineral ore has been ground and comminuted to the desired size, the comminuted material is transferred for further processing. This can be a continuous process or batch process wherein the diluted comminuted material goes through a flocculation step or stage to promote phase separation and concentration of the ore being processed. The flocculants promote aggregation of the fine particles which is an important component of mineral recovery strategy.
We have found through extensive research that certain flocculants in the presence of anionic grinding aids can enhance the processing of the mineral ore by increasing the desired phase separation in the flocculation stage of the mining process. In particular we have found that anionic grinding aid when used in combination with certain cationic flocculants, carboxylated and/or sulphonated anionic flocculants and terpolymers significantly reduce negative interactions between the grinding aid and flocculant, thereby enhancing the processing of the ore and improving efficiency. The mining industry is constantly seeking new additive technologies that will increase the efficiency of the comminution process and overall ore recovery in mineral mining operations.
All parts and percentages set forth herein are on a weight-by weight basis unless otherwise indicated.